1. Field of the Invention:
This invention relates to a method of producing frozen food which requires at least two steps of freezing. It is applicable to the food which is a liquid or semifluid at normal room temperature, such as a cream croquette or decorated ice cream.
2. Description of the Prior Art:
The frozen food of the type to which this invention is applicable has hitherto been produced by a gyrofreezer of the type as disclosed in Japanese Utility Model Publication No. 28805/1982 and shown in FIG. 3, or a tunnel freezer. The gyrofreezer shown in FIG. 3 comprises a drum 1 and two chain belts 2a and 2b which are wound about the drum 1 spirally and in parallel to each other. Each of the belts has an inlet end and an outlet end which are connected to the outlet and inlet ends, respectively, of the other belt, so that they may form an endless belt. The food to be frozen is fed to the endless belt at the bottom thereof and the frozen food is removed therefrom at the top thereof. Both of the former and latter steps of freezing have hitherto been performed at a substantially equal temperature of -10.degree. C. to -18.degree. C.
The production of frozen food in a conventional way as hereinabove described has, however, a number of problems. It requires a great deal of time. When a frozen croquette is, for example, produced, the intermediate product made by the first step of freezing must be separated from a tray and coated by battering or breading, but is difficult to separate from the tray. Moreover, the material with which it must be coated fails to adhere to it satisfactorily.